Insulin-dependent diabetes mellitus (IDDM) is the most common endocrine disorder of childhood, affecting over 150,000 children and adolescents. It is a life-long disease, with no known cure, that is associated with a number of serious neurological and vascular complications. By combining the skills and experience of two disciplines--psychology and pediatric medicine--we hope to accomplish two long-term objectives: (1) the identification of psychosocial variables critical to the management and control of diabetes in the child; and (2) the development of effective treatment and prevention programs to improve the quality and length of life in this population. Our research is characterized by: (1) focus on psychological variables presumed to be related to management and health in the IDDM child; (2) the use of adequate measures of the psychological and health variables selected for study; (3) the study of five specific psychological variables that are presumed to have a direct bearing on diabetes control--patient and parent knowledge about diabetes, patient and parent attitudes toward diabetes and compliance with management tasks; (4) the use of multivariate techniques to study psychological variables in combination; and (5) the assessment of both child and parent variables and the child's age as important contributing factors. We believe that this approach represents an improvement and a marked departure from past research efforts in the area. The specific aims of our proposed research plan are: (1) to cross-validate findings from a multivariate study recently completed in which the five psychological variables specified above were studied within the context of the child's level of diabetes control; (2) to conduct a longitudinal study focusing on these same variables in both newly diagnosed IDDM children and youngsters who have had diabetes for 1 year or longer; and (3) to carry out studies designed to further our understanding of three of the variables we have selected for inquiry--diabetes control, compliance and patient knowledge. Study #1 will address the utility of an empirically based method of determining diabetes control and will explore factors relevant to physicians' judgements of this variable. Study #2 will compare exercise and dietary habits of good vs poorly-controlled patients with nondiabetic yongsters used as a reference group. Study #3 will assess the utility of individual symptoms in the prediction of IDDM adolescents' blood glucose levels. Findings from all of these studies should provide the necessary data base for the design of successful intervention and prevention programs and the study of other psychological variables thought relevant to diabetes management.